Which of the following process/processes destroy/destroys the magnetic properties of a bar magnet?I. Cutting into two piecesII. HeatingIII. BeatingIV. Sealing

 On heating strongly or hammering, the kinetic energy of the molecules increases and therefore, the molecular alignment gets disrupted. Hence, the molecules go back to the closed chain arrangement due to thermal agitations. Thus, the magnet gets demagnetised.